From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Graph analysing power losses in a Phantom II short type silencer exhaust system at different RPMs.
| Identifier | ExFiles\Box 6\7\ 07-page173 | |
| Date | 2nd November 1931 guessed | |
| LOSSES TO EXHAUST SYSTEM P.I. RM.{William Robotham - Chief Engineer} P35 ANALYSIS OF COMPLETE P.II. SHORT TYPE SILENCER 4.6 C/R 108° MASKED VALVE CAMSHAFT TWIN CARBS 1-1/4" DIA. THROAT B.H.P. R.P.M. CURVE 1: OPEN EXHAUST CURVE 2: MANIFOLD ONLY CURVE 3: MANIFOLD AND DOWNT-AKE CURVE 4: MANIFOLD, DOWNT-AKE AND EXPANSION BOX THE B.H.P. RISES BY 3 WHEN THE INTERMEDIATE PIPE IS ADDED TO CURVE 4. THIS EXPLAINS WHY CURVE 4 IS MUCH THE SAME AS CURVE 2 ON RM.{William Robotham - Chief Engineer} P33. | ||